There are many spray gun type applicators known in the art of lawn and garden chemical application. Typical hose end lawn or garden sprayers are aspirator units which apply fertilizers, pesticides or other chemicals at a fixed, low dilution ratio. To utilize concentrates which must be diluted to high ratios, the user normally predilutes the concentrate with water. This is accomplished by volume measurement of the concentrate with a spoon, cap or other measuring device into a sprayer mix jar. Water is then added to obtain the proper premix concentration. The prediluted concentrate is then further diluted to the final dilution ratio as the sprayer is operated.
Such predilution procedures require the manual handling of concentrated chemicals with its attendant risks. Moreover, the user must generally purchase the concentrate in larger quantities than are necessary for a single application and, thus, containers of the concentrated chemical must be stored for extended periods after they have been opened. On the other hand, devices which attempt to avoid predilution by diluting the concentrate at a high ratio in one (1) step are not satisfactory because of very poor accuracy. The concept of two-step mixing or dilution of chemicals, including such use in spraying devices is known. See, for example, U.S. Pat. Nos. 2,006,437; 2,599,678; 2,711,928; 2,760,820; 3,104,823; 3,181,797; 3,499,606; and 4,027,822. However, the devices shown in these patents are either cumbersome or otherwise unsuitable for garden spray devices. U.S. Pat. No. 3,165,114 issued to Garrett discloses a dispensing package of fluid soluble material capable of use with a standard feed mixer device. Some of the flowing water is diverted down through a nipple and inlet tube into the bottom of the package. Suction draws the dissolved material through an outlet tube. The device requires water to constantly flow through it, and does not provide a barrel valve which could shut off or control the flow.
U.S. Pat. No. 3,198,438 issued to Hultgren, et al. requires a trigger action to push a tapered plug out of an aperture, allowing water to flow into a mixing chamber to create a venturi suction to draw fluid out of a collapsible container. U.S. Pat. No. 3,255,972, also issued to Hultgren, et al. discloses a disposable container for use with sprayers of the type disclosed in the '438 patent. U.S. Pat. No. 3,554,450, issued to D'Muhala teaches a spray gun which accommodates removable cartridges containing various solids or liquids. An end cap is unscrewed to control water through a mixing chamber and out a nozzle.
U.S. Pat. No. 3,915,191 discloses a water mixing device for a shower which may be fitted to the taps of a bath. A selector valve selectively permits water from an inlet chamber to flow through various enclosures of a second chamber. At least one (1) enclosure has a container to receive a soluble substance such as soap. No initial dissolution of the soap is provided for, and the soap is transported by direct flow of the water, and not drawn by aspiration.
U.S. Pat. No. 4,491,254 issued to Viets, et al. teaches an applicator for dispensing a chemical in dilute aqueous form. The applicator has two (2) containers. The second container receives a chemical which has been diluted with water from the first container. A two-position, rotatable valve directs the flow of water into either the first container to predilute a chemical, or to flow across an aspirator to mix with the prediluted chemical and discharge it through the exit end of a passageway. Viet's device requires removing caps from the containers to add chemicals, and to thread the containers together to attach them, a cumbersome and potentially unsafe procedure. The valve taught by Viets, et al. only has two (2) positions. Water is constantly flowing either into the second container to dilute a chemical or through the passageway. An operator must use a conventional nozzle, which must be specially adapted to attach to the applicator to turn the water on or off to control the flow.
U.S. Pat. No. 5,213,264 to Styne teaches a spraying apparatus having a sprayer head and a cartridge. A barrel valve controls whether an entering fluid flows directly into a mixing chamber, or flows through a tube into the cartridge, or does not flow at all. A membrane is required at the top of the cartridge, and is punctured by sprayer head tubes during attachment. U.S. Pat. No. 5,332,158 to Styne teaches a spraying device with an interchangeable cartridge. More specifically, U.S. Pat. No. 5,332,158 teaches a sprayer having a fluid inlet port which directs fluid into a mixing conduit. An aspirator port connects the mixing conduit with a second fluid in the cartridge. A vent port in the sprayer head connects with a vent in the cartridge to reduce the pressure differential in order to allow proper aspiration and reduce leaks. A nozzle means permits a controlled jet spray.
The prior work is limited in the attempts to easily, economically, safely, and environmentally provide a device to dilute and dispense various insecticides, herbicides, cleaners, and fertilizers. There is a need for a spraying device that keeps the chemical in a closed system until the operator engages the trigger. There is also a need for a sprayer in which the metering orifice is preset so that the end user does not have to worry about adjusting the water to chemical ratio.